4.1: Mixing Console: A Mono I/p Signal Path

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4.1: Mixing Console: A mono I/P signal path GrassCA 1 Section 5: Signal path and processing 5.1 5.2 5.3 5.4 5.5 • Channel Insert point and Dynamic Processing • Gates and Compressors • Frequency - Equalisation •Time Domain Processors – Send effects • DSP and Gain stages GrassCA 2 Section 5: Signal path and processing “'Dynamics Processing' describes the field of audio signal processing concerned with managing the volume level of audio signals over time. By making alterations to signal level - at speeds often measured in milliseconds - dynamics processors can dramatically alter the perceived loudness, clarity, consistency and power of live or recorded sound. When mixing signals together, correct dynamics processing can help both to integrate and separate elements of a mix sometimes simultaneously - and an understanding of dynamics is vital to good mix engineering” JISC Media 2011 GrassCA 3 Section 5.1:Channel Insert Dynamic processing: Drum Gating Vocal/Bass Compression Input Gain Input level Meter Insert Point EQ GrassCA 4 5.1: Direct Output: Pre-Post Processing Pre or Post EQ (Jumper Selection) Input Gain Insert Point EQ Direct Output (Post Insert): Multi-track Recording Monitor Desk Sends GrassCA 5 5.1: Dynamics Processing Channel gain Channel gain dB - dB + dB Compression New Gain Level EQ f (Hz) x dB GrassCA 6 5.1: Signal Processing: Dynamics Audio dynamics are controlled/sculpted with dynamic processing: Gates, Compressors and Expanders GrassCA 7 5.2: Dynamics Processing: Gating Threshold: when the signal goes above, the gate is told to open Range: Amount of level allowed to pass when gate is shut GrassCA 8 5.2: Dynamics Processing: Gating Attack: set the time fast enough to capture the drum’s transient, but not so fast that the gate clicks. Hold time : how long (ms) the gate remains open once it’s fully open. Too short can clip end of the drum’s ring Decay(Release) time: determines how quickly the attenuation increases once the signal goes back below threshold. GrassCA 9 5.2: Dynamics Processing: Gating Processors: Gates Noise Gates used primarily cut out unwanted noise before and after the wanted signal. Commonly used for drums to tighten the signal i.e. Gated kick and snare, reducing the ring on open toms. Diagram shows tightened signal in Green GrassCA 10 5.2: Dynamics Processing: Compression A compressor/limiter reduces the dynamic range of an audio signal. Simply put, it makes quieter things louder, and louder things quieter. Several controls are available, such as attack and release times, threshold levels, and compression ratios. We control the amplitude levels of the signal. Limiters safeguard against signal peaks (clipping), preventing transient peaks which would be too loud or distort. In Live Sound they are placed in the signal path prior to system power amplification to safeguard against signal distortion and equipment protection. e.g. an amp and a speaker reproduce a high level clipped waveform. GrassCA 11 5.2: Dynamics Processing: Compression Threshold: Level where comp reacts to I/P Knee and Ratio (affects amount of GR) Gain reduction(GR) vvvvvvMake-Up Gain(O/P) GrassCA 12 5.2: Dynamics Processing: Compression Link: Compressors 1:1 2:1 dB 4:1 20:1 dB ©JISC Media 2011 GrassCA 13 5.2: Dynamics Processing: Limiting Link: Limiting ©JISC Media 2011 GrassCA 14 5.2: Dynamics Processing: Limiting ©JISC Media 2011 GrassCA 15 5.3: Frequency Processing: Equalisation f (Hz) x or ÷ dB LF (shelving) Lmid (Swept) Hmid (Swept) HF(Shelving) GrassCA Equalisers 16 5.3: Audio Processing: Frequency: Shelving GrassCA 17 5.1: Audio Processing: Frequency Pratical EQ GrassCA 18 5.4: Time Domain : Send Effects Pre fader: Monitor Mixes Aux send Fader O/P Bus Post fader: Time domain FX: Reverb, Delay GrassCA 19 5.4: Audio Processing: Time Domain: Delay Time: Seconds between repeats Feedback: Repeats Number Mix: Dry vs. Wet GrassCA 20 5.4: Audio Processing: Aux Sends Stereo Return Channel Mono Send % dB ST GrassCA 21 5.5: Main System DSP: Speaker Management Loudspeaker Management GrassCA 22 5.1: Audio Processing: Recap Dynamic Inserts and EQ Source Process Output Channel - Master - Group GrassCA 23 5.1: Audio Processing: Recap Aux SENDS-Blend Wet and dry Wet % dB Process Dry Source Output GrassCA 24 5.1: Audio Processing: Recap • Pre-Amp • Compression • O/P Bus Gain Frequency • HPF • Ch. EQ • Master EQ GrassCA • Reverb(FX) • Delay(FX) • Alignment Time 25